The present invention relates to variable valve actuating apparatuses or systems for controlling opening and closing timings of intake valves and exhaust valves of internal combustion engines provided with exhaust turbochargers.
Japanese Patent Application Publication No. 2003-3871 discloses a variable valve actuating system for an internal combustion engine provided with an exhaust turbocharger. When detecting that the engine is in a state of acceleration, this variable valve actuating system, at an initial stage of acceleration, advances opening and closing timings of an exhaust valve of the engine with respect to a normal setting employed before the detection that the engine is in the state of acceleration, and reduces a period of valve overlap in which both of the exhaust valve and an intake valve are open. After the initial stage of acceleration, the variable valve actuating system advances opening and closing timings of the intake valve. This process is intended for rapidly increasing the rotation speed of an exhaust turbine of the exhaust turbocharger in order to rapidly increase the boost pressure of the exhaust turbocharger at an initial stage of acceleration of the engine.